Electrical switchable room-temperature magnetic skyrmions in multiferroic MXene

Two-dimensional (2D) transition metal carbides and nitrides (MXene) host a plethora of interests, e.g., energy storage and conversions, and intriguing quantum phenomena ranging from electronic topological properties to superconductivity. However, topological magnetism is still a missing piece in MXenes. Here, via first-principles calculations, we validate the existence of significant Dzyaloshinskii--Moriya interaction (DMI) in 2D multiferroic MXenes, where the magnitude of DMI scales with the strength of electric dipole of the MXenes. Moreover, using atomistic spin model simulations, we demonstrate that room-temperature (RT) magnetic skyrmions can be spontaneously stabilized at monolayer ${\mathrm{Co}}_{2}\mathrm{C}{\mathrm{F}}_{2}$. The chirality of DMI can be tuned via ferroelectricity effect and, consequently, the skyrmions. We further show that a proper van der Waals substrate can effectively enhance the magnetic anisotropy of ${\mathrm{Co}}_{2}\mathrm{C}{\mathrm{F}}_{2}$ through interlayer charge transfer, while the tunable DMI and RT skyrmions can also be maintained. These results prove that MXenes and their heterostructure can be promising candidates in fabricating ultrathin skyrmionic devices and pave the way for the RT electrically controllable skyrmions toward spintronic applications.